     (illegal-argument "Cannot store layout in :text format which does "
                       "not come from a concept lattice."))
   (let [nodes       (vec (keys (positions layout))),
-        node-number (comp inc (seq-positions nodes))]
+        node-number (comp inc (seq-positions nodes)),
+        annotation  (annotation layout)]
     (with-out-writer file
       ;; Node
       (doseq [n nodes]

        (println (str "Edge: " (node-number x) ", " (node-number y))))
      ;; Object
      (doseq [n nodes,
              g (first n)]
        (println (str "Object: " (node-number n) ", " g)))
      ;; Attribute
      (doseq [n nodes,
              m (second n)]
        (println (str "Attribute: " (node-number n) ", " m)))
      (println "EOF"))))



(add-layout-input-format :simple
                         (fn [rdr]
                           (= "conexp-clj simple" (read-line))))

(define-layout-output-format :simple
  [layout file]
